77 lines
1.6 KiB
Markdown
77 lines
1.6 KiB
Markdown
# Python:更多词典
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> 原文：<https://www.pythonforbeginners.com/dictionary/python-more-dictionarys>
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### 什么是字典？
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字典是具有“键”和“值”的条目的集合。
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字典是可变的。您不必重新分配字典来对其进行
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更改。
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它们就像列表一样，除了没有指定的索引号，
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而是由你自己编索引:
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### 示例 1
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```py
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testList = ["first", "second", "third"]
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testDict = {0:"first", 1:"second", 2:"third"}
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```
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Python 中的字典是用{}括起来的，要创建一个字典，必须提供一个键/值。
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字典中的每个键必须是唯一的。
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冒号放在键和值之间(键:值)
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每个键:值对由逗号分隔
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### 示例 2
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```py
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>> phonenumbers = {'Jack':'555-555', 'Jill':'555-556'}
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phonebook = {}
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phonebook["Jack"] = "555-555"
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phonebook["Jill"] = "555-556"
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print phonebook
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{'Jill': '555-556', 'Jack': '555-555'}
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```
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字典只有一种工作方式，要从字典中获取一个值，必须输入键。
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您不能提供值并获取密钥。
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### 示例 3
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```py
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phonebook = {}
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phonebook["Jack"] = "555-555"
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phonebook["Jill"] = "555-556"
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print phonebook['Jill']
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555-556
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```
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### 键/值用法
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```py
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To add a key / value pair in a dictionary
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>>phonebook["Matt"] = "555-557"
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To change a key / value pair:
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>>phonebook["Jack"] = '555-558'
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To remove a key / value pair, use del
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>>del phonebook["Jill"]
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To see if a key exists, use has_key() method
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>>phonebook.has_key("Matt")
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To copy whole dictionary, use the copy() method
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phonebook2 = phonebook.copy()
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```
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在存储查找结果时，我通常使用字典。 |